For the present LCD TVs, an alternate current (AC) of an AC power supply is converted into a low-voltage direct current (DC) by an AC-to-DC power supply, and the specification of outputting DC includes 5V, 12V, 24V, and 48V depending on different manufacturers. The low-voltage DC is supplied for the use of low-voltage loads of a television, and the low-voltage loads include devices such as a display driven panel, an audio/video processing circuit board, and a speaker, etc, and this low-voltage DC is also outputted to a high-voltage power converting system. The high-voltage power converting system steps up the low-voltage DC and then outputs the DC to the high-voltage load of the high-voltage power driven television, and the high-voltage load is a backlight module having a gas discharged lamp (such as a cold cathode ray tube).
However, the digital LCD TV only changes the video signal processing method to the digital coding for its application, and thus an LCD TV can have many digital functions such as adding a video memory card reader to the digital TV, so that after a user inserts a digital video memory with photos taken by a digital camera, the LCD TV is converted into an LCD electronic album for viewing the photos. Further, a radio frequency modulator function is added to the LCD TV or an audio/video player is connected directly to the LCD TV, so that the LCD TV can play music directly. However, all power systems of the LCD TV are turned on, if a user selects the function of viewing photos or the function of playing music from the present LCD TVs. Therefore, the components still consume electric power even if these components are not used for the desired operating function. Particularly, if a user only uses the function of playing music and the backlight source system and the video processing system are activated, it increases the power consumption and shortens the life of components as well as the LCD TV.